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Tire pressure gauge always a wise investment The best performers are all $7.50 and up price range By Eric Lai - Toronto Star Tests have shown that more than 90 per cent of cars on the road have improperly inflated tires. These motorists suffer needless wear and waste gas: every 1 psi (7 kPa) of underinflation costs up to 0.8 per cent in lost gas mileage. According to Goodyear Canada, tires lose about 1 psi per month under normal conditions. A change of seasons will also alter tire inflation, each 5 C drop in outdoor temperature results in a 1 psi reduction in tire pressure. Ideally, tires should be checked cold every two weeks, but even once a month is better than never. Recommended pressures will be found in your owner's manual. I tested a number of inexpensive tire gauges for accuracy (compared to "certified accurate" readings from a pro-grade meter). The $1 unit from the dollar store was garbage. It was off by as much as 17 psi, but other low-cost units were within 2 psi. The best performers were in the $7.50 and up price range; they were good to within 1 psi. The lower-priced units were acceptable, with readings accurate to within 2 psi. Surprisingly, the most expensive unit at $24 was consistently low by 2 psi. Dial units performed no better than pencil-type gauges in my tests, and the electronic model ($10) did neither better nor worse than conventional designs. A word of caution: don't rely on the gas station compressor's gauge, as these are notoriously inaccurate. Tire pressure gauges are sold at auto and hardware stores. The units tested (over $ 1) were purchased from Canadian Tire. |